An injectable, self-healing composite hydrogel with enhanced near-infrared photo-antibacterial therapeutic effects for accelerated wound healing

Antibacterial hydrogels with injectable and self-healing properties have attracted much attention in the field of wound dressings because they not only can prevent bacterial infections, but also meet the basic needs for wound healing. However, how to achieve high antibacterial efficacy and low drug resistance for hydrogels is still a challenge. Herein, an injectable, self-healing, near-infrared (NIR) photosensitive antibacterial hydrogel composed of CuS-grafted-curcumin (CuS@C) and carboxymethyl cellulose modified with aldehyde groups and hydroxypropyl trimethyl ammonium chloride chitosan is prepared for wound dressings. The p-n junction formed between curcumin and CuS promotes separation of electron-hole pairs, enhances the mobility of photogenerated charges, and destroys the conjugated structure of curcumin simultaneously consequently increasing the photocatalytic activity. CuS@C is immobilized and distributed uniformly in the hydrogel via the π-π conjugation ring. The hybrid hydrogel exhibits excellent antibacterial activity after irradiation with 808 NIR light for 10 min due to the enhanced photodynamic and photothermal antibacterial effects. In addition, the hybrid structure improves the biocompatibility of CuS and expedites infected-wound healing at a mild temperature of 45 ℃. This organic/inorganic hybrid is shown to be an excellent wound dressing for the treatment of bacterial-infected wounds.